Firewall that monitor application outbound traffic is high maintenance and can often cause problems. There are situations where they can augment systems protection against attacks, and years ago they were the only tools available, so arguably using them was worth the trouble. But nowadays there are better things you can use with less potential for causing problems.

Unlike XP, Vista and W7 built-in firewall is capable of filtering outbound traffic -- but it is by default disabled -- so even if you feel you need outbound filtering, e.g., to prevent some apps from automatically phoning home, you don't need to use a third party firewall.

If you are using an AV that actively scans HTTP traffic like Kaspersky, all the traffic may appear to the firewall to be originating from the AV thus rendering application outbound monitoring useless.

For mobile systems such as your netbook, you do want to make sure that you have a firewall running since it may not always be connected to your own private network, Windows firewall is good enough for that.

For desktops systems, I keep the Windows firewall on even though I'm behind a hardware firewall, but others feel that its not needed.

Does the thirdparty software firewall prevent inbound attacks then, or is the combination of a router and the Windows firewall all theat is needed ? This leaves only the need for an anitvirus software..??